Zwitterionic poly(sulfobetaine methacrylate)s in water: from upper critical solution temperature (UCST) to lower critical solution temperature (LCST) with increasing length of one alkyl substituent on the nitrogen atom

2018 ◽  
Vol 9 (43) ◽  
pp. 5257-5261 ◽  
Author(s):  
Ning Wang ◽  
Bryan T. Seymour ◽  
Evan M. Lewoczko ◽  
Ethan W. Kent ◽  
Ming-Li Chen ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Lower Critical Solution Temperature ◽  
Alkyl Substituent ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Upper Critical Solution Temperature ◽  
Alkyl Length

Increasing the alkyl length on nitrogen of the polymer changes behaviour from UCST, to soluble, LCST, and insoluble.

Polymer Fractionation at a Lower Critical Solution Temperature Phase Boundary

1967 ◽  
Vol 40 (5) ◽  
pp. 1544-1552
Author(s):  
C. H. Baker ◽  
C. S. Clemson ◽  
G. Allen
Keyword(s):  
Molecular Weight ◽  
Phase Boundary ◽  
Lower Critical Solution Temperature ◽  
Solution Temperature ◽  
Temperature Phase ◽  
Critical Solution Temperature ◽  
Upper Critical Solution Temperature ◽  
Two Samples ◽  
Polymer Fractionation ◽  
Molecular Weight Fractions

Abstract The influence of pressure on a lower critical solution temperature is much more pronounced than on an upper critical solution temperature. Accordingly it is possible to control phase separation at a LCST phase boundary under isothermal conditions by merely adjusting the pressure on the system. An apparatus has been constructed to investigate the isothermal fractionation of polyisobutene in which precipitation is controlled by pressure. Two samples of polyisobutene of Mv=1.76×106 and 9.0×104 have been fractionated in isopentane solution so as to yield up to six and nine fractions respectively. The integral molecular weight distribution curves thus obtained are compared with those obtained from conventional fractionations at an UCST. The sensitivity of the method is poor with regard to the separation of low molecular weight fractions and degradation occurs at the higher temperatures to an appreciable extent.

scholarly journals Designing the thermal behaviour of aqueous biphasic systems composed of ammonium-based zwitterions

2017 ◽  
Vol 19 (17) ◽  
pp. 4012-4016 ◽  
Author(s):  
Ana M. Ferreira ◽  
Helena Passos ◽  
Akiyoshi Okafuji ◽  
Mara G. Freire ◽  
João A. P. Coutinho ◽  
...  
Keyword(s):  
Thermal Behaviour ◽  
Lower Critical Solution Temperature ◽  
Water Soluble ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Aqueous Biphasic Systems ◽  
Upper Critical Solution Temperature ◽  
Aqueous Biphasic ◽  
Biphasic Systems

The design of the thermal behaviour – from an upper critical solution temperature (UCST) to a lower critical solution temperature (LCST) – of aqueous biphasic systems composed of water-soluble ammonium-based zwitterions.

scholarly journals Influence of cyclodextrin on the UCST- and LCST-behavior of poly(2-methacrylamido-caprolactam)-co-(N,N-dimethylacrylamide)

2014 ◽  
Vol 10 ◽  
pp. 1951-1958 ◽  
Author(s):  
Alexander Burkhart ◽  
Helmut Ritter
Keyword(s):  
Free Radical ◽  
Nmr Spectroscopy ◽  
Lower Critical Solution Temperature ◽  
Solution Temperature ◽  
Radical Mechanism ◽  
Methacryloyl Chloride ◽  
Critical Solution Temperature ◽  
Free Radical Mechanism ◽  
Upper Critical Solution Temperature ◽  
Lcst Behavior

The monomer 2-methacrylamido-caprolactam (4) was synthesized from methacryloyl chloride (3) and racemic α-amino-ε-caprolactam (2). Copolymerization of 4 with N,N-dimethylacrylamide (5) was carried out by a free-radical mechanism using 2,2’-azobis(2-methylpropionitrile) (AIBN) as an initiator. The new copolymers show a lower critical solution temperature (LCST) in water and an upper critical solution temperature (UCST) in ethanol, 1-propanol, and 1-butanol. The solubility properties of the copolymers can be influenced significantly by the addition of randomly methylated β-cyclodextrin (CD). The complexation of the copolymers with CD, was confirmed by the use of ROESY-NMR-spectroscopy.

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